Palladium-Coated Kieselguhr for Simultaneous Separation and Storage of Tritium

Palladium finely dispersed in a substrate of kieselguhr (diatomaceous earth) has been successfully used for tritium storage, separation and pumping for a number of years at the Savannah River Site (SRS). Recently SRS has designed and built a new Pd/kieselguhr flow through bed (FTB) prototype for separating tritium from other gases and simultaneously storing the tritium on palladium. The FTB prototype uses single-pass liquid nitrogen for cooling during tritium absorption/loading/storage and electrical heaters for desorption/unloading of tritium. Fourteen (14) hydrogen absorption/desorption or loading/unloading cycles have been conducted with the new FTB prototype. Test results show that all design performance objectives have been successfully achieved: recover >95% of hydrogen gas from feed gas, <5% hydrogen in discharge gas, and >99.9% hydrogen in the desorbed product gas. This paper will discuss the design and operation of the FTB, and results of performance tests such as separation efficiency, hydrogen/tritium storage capacity and temperature profiles during prep cooling, hydrogen loading and unloading.